Not all Kulian soldiers are elite veterans or drugged slaves. Some in fact are competent with weapons, but do not have the skill to enter the Deathbringers. They are put into the third formation, normally known only as "The Infantry."
Most of the Infantry are humans, attracted by the good pay and inevitable respect that comes from being a soldier. They have to endure hard training, but most of them survive. The result is a useful core of soldiers that can be used for many purposes. They are formed into different regiments and companies. For instance Darkul, formerly a miner, joined the Third Pike Regiment of the Infantry, trained for defensive purposes against cavalry.
Joining the Infantry is not difficult and in fact encouraged by the High Priest and his advisors, for such an ambitious nation as Kul can always use soldiers.